Preparation of coffee.



I cafl'ein, without L'UDWIG ROSELIUS, OF BREMEN, GERMANY.

PREPARATION OF COFFEE.

No Drawing.

Specification of Iietters Patent.

Patented Aug. 15, 1911.

Application filed March 19, I909. Serial No. 484,365.

To all whom it may concern:

Be it known that I, LUDWIG Rosnnrus, a citizen ofthe free and hanseaticcity of Bremen, Germany, residing at Bremen, Germany, have inventedcertain new and useful Improvements in the Preparation of Oofiee, ofwhich the following is a specification.

This invention relates to a preparation of coffee, whether ground orunground, and further relates to the product derived from the manner oftreating the coffee, and has for its object, to remove from roastedcofl'ee destroying the aromatic or other valuable properties of thecoffee.

Numerous attempts have been made for the purpose of removing cafieinfrom roasted coffee, but such attempts have been unsuccessful owing tothe fact that after a treatment of the coffee, the caiffein has not onlybeen removed, but the aromatic, as well as the other valuableconstituents of the coffee destroyed, consequently the coffee after thetreatment could not be used as a satisfactory beverage.

Therefore, it isthe object of this invention to provide a method oftreating roasted coffee, which removes the cafi'ein without destroyingor injuring the other valuable properties whereby the coffee aftertreatment can be used as a satisfactory beverage.

To define specifically a method of treating coffee in accordance withthis invention, reference will be had to the following :-rGreen coffeecontaining cafl'ein isroasted, after the coffee has been roasted and thecaifein still remaining in the coffee, the roasted coffee is preferablymoistened by subjecting the coffee to air containing a degree ofmoisture not sufficient to cause waterpearls to be precipitated directlyon the superficies of the beans, which might deteriorate the structureor quality of the bean. The coffee beans are dryer than the airsurrounding them, the air, which is more moist than the beans, is onlymade to pass the beans, causing the beans to gradually absorb thedesired degree of moisture. The period for the indirect moistening ofthe coflee is preferably twenty-four hours.- By indirectly moisteningthe coffee it will absorb the necessary amount of moisture so asto'loosen the structure thereof, or the cellular tissue, so as toprepare for the decomposition of the cafi'ein salts, as the caflein iscontained in the coffee in the shape of salts which are hardly. solubleat all in volatile solvents manner, that is to say,

alone. After the coffee has been moistened for the desired period, it isheated to a tem perature of from about 70 to 90 C. This manner ofheating the coifee to such an extent causes the coifee to remain in amoistened state. In this connection it will be stated that it ispossible to heat water to a temperature of from 70 to 90 degrees withoutevaporating it and if the moisture is in the coffee beans, it is stilleasier to inhibit the evaporation at such a low temperature and undersuch conditions the beans are not thoroughly dried after being submittedto the temperature referred to for the reason that the beans stillcontain a degree of moisture. It is then subjected to electrolysis, andin this connection it will be stated that the coffee is placed into anopen wooden trough, on the insides of its two walls two copper platesare fixed, one constituting a positive and the other thenegative,'suitable circuit wires are connected to the plates. The sub-'ecting of the coffee to electrolysis causes the decomposition of thesalts of cafiein. During the electrolyzing step a suitable medium toheighten the effect of the current is added, such medium by way ofexample being sodium chlorid. In this connection it will be stated thatthe coffee prior to placing it into the trough, is placed in a woodendrum together with the sodium chlorid and is agitated sufiiciently tohave the solution evenly distributed on the superficies of the bean,after which the coffee is placed in the wooden trough and treated by theelectric current as described.

After the salts of caifein have been decom- I posed the caflein isextracted in a known the coifee is subjected to a dissolvent ofcafi'ein, preferablypne which dissolves only the calfein and as littleas possible of the other aromatic constituents of the coffee, forexample, as that set forth in Letters Patent #897,840, the solvent beingbenzin, or a mixture of benzin and alcohol.

After the caffein solvent the colfee is then placed in a roastingapparatus and dry steamis passed through the coffee which removes alltraces of the solvent. After all the traces of the solvent have beenremoved, the coffee is then thoroughly dried, or brought to a state ofdryness whereby it is ready for use.

By moistening the roasted coffee in the manner as stated, the aromaticproperties has ben extracted by the moistening the roasted coffee,

of the coffee are not injured or impaired, such .would be the casehowever if the coffee had directly precipitated thereon the Water, or ifthe cofiee is soaked.

By the method heretofore set forth, roasted cofl:ee can be freed ofcafi'ein without impairing to any material extent the aro-- thensubjecting caifein in the beans by electrolysis, then extractingthecaffein by a solvent which does not impair the other valuableconstituents of the cofiee, then subjecting the coffee to dry steam toremove the traces of the extracting solvents, and: then bringing thecoffee to a state of dryness by heat whereby the coffee is ready foruse.

In testimony whereof I aflix my signature, in presence of two witnesses.

LUDWIGr RQSELIUS.

Witnesses:

N. LOUIS BOGAN, SYLVANUS D. WARD.

